North-West Europe is not a well defined term. It is clearly some subdivision of Western Europe, but the exact subdivision implied depends on context.

Geographically it is almost always used to include the United Kingdom and Ireland; the northern and western parts of France and Germany; the Benelux countries; and Scandinavia (though possibly not Finland). It would normally exclude the Iberian peninsula, Italy; Switzerland, and southern and western parts of France and Germany, might be included, but Austria would not be. This usage is helpful when discussing issues of climate or biology. Broadly speaking, it represents the area whose climate and biogeography is significantly modified by the Gulf Stream.

Socially, "North-West Europe" is sometimes used to refer to the group of nations within this broad geographical area where English is either the first language or is known and spoken by all educated people; these nations are felt to share some cultural traits (for example, a history of Protestantism) that differentiate them from their Mediterranean or Slav fellow-Europeans. This leads to much the same definition as the geographical one above, but would more definitely exclude France (and, less certainly, Belgium or at least Wallonia).

Politically, some europhobic British commentators exclude the UK and Ireland from the definition from any part of Europe.

In British and military history, North-West Europe has been used to refer to the land campaigns in that approximate area during World War II. Two separate battle honours were awarded to regiments who took part in theses campaigns "North-West Europe Campaign of 1940" and "North-West Europe Campaign of 1944-1945". The North-West Europe Campaign of 1940, during the Battle of France, was restricted to the Belgium and the French Channel ports. The North-West Europe Campaign of 1944-1945 started with the landings in Normandy and ended with Field Marshal Montgomery taking the German military surrender of all German forces in Holland, Northwest Germany and Denmark on Lüneburg Heath in Northwest Germany was fought by the British 21st Army Group. In the First campaign the French Army was responsible for the rest of the Western Front from Luxembourg to Switzerland, as were the American 12th Army and 6th Army groups during the second campaign.